The molding of metallic articles is a historic manufacturing technique, with single and multiple cavity molds being quite common. Moreover, the art abounds with automatic molding apparatus.
When the entire article is made of a single type of metal it appears that little can be done to improve the historic technique. However, when the finished article comprises two distinct metallic components, and particularly when it is desired that one component physically embrace at least a portion of the second component, the complexity of the manufacturing process is significantly increased.
Excellent insight as to the difficulties attendant upon the manufacture of such items can be obtained by reference to the procedure by which simple tire weights are fabricated.
The entire weight normally comprises a lead body portion and a steel mounting clip. The lead of the body portion embraces at least a portion of the mounting clip, and as such, the lead is generally cast about a portion of the mounting clip which must be painstakingly oriented in order not only to effect the desired mechanical bonding therebetween but also to assure that the steel clip will not cause the lead to rupture during use, or even as the weight is being mounted. As such, the manufacture of such wheel weights has, heretofore of necessity, been rather labor intensive.
It is, therefore, a primary object of the present invention to provide an apparatus for molding metallic articles wherein an object to be encapsulated, in whole or in part, within the cast metal is accurately positioned within the mold by virtue of the unique molding apparatus and without painstakingly intricate manual manipulation.
It is another object of the present invention to provide an apparatus for molding metallic articles, as above, wherein the molten metal is injected directly into the cavity at the minimal pressure required, thereby eliminating not only feed runs but also virtually eliminating any flash.
It is a further object of the present invention to provide an apparatus for molding metallic articles, as above, wherein the mold closing mechanism sequentially effects injection of the molten metal, thus assuring the safety feature that the molten metal is not injected unless the mold is closed.
It is yet another object of the present invention to provide an apparatus for molding metallic articles, as above, wherein an application that would normally be expected to require a three-part mold--the third part being required to move generally transversely the direction in which the other two parts move--can be accomplished by a relatively uncomplicated two-part mold.
It is a still further object of the present invention to provide an apparatus for molding metallic articles, as above, which is readily adaptable for the production of wheel weights and wherein positioning means is employed rotatably to orient the mounting clip with respect to the mold cavity in order to maximize the mechanical bonding between the mounting clip and that portion of the weight that is being molded.
These and other objects of the invention, as well as the advantages thereof over existing and prior art forms, which will be apparent in view of the following specification are accomplished by means hereinafter described and claimed.
In general, an apparatus for molding metallic objects which embodies the concept of the present invention is particularly adapted for use in the manufacture of wheel weights.
A stanchion is secured to the frame of the apparatus, and first and second support plates are disposed within the stanchion for movement along the longitudinal axis of the stanchion. First and second mold sections are carried, respectively, on the first and second support plates.
An activating means is mounted on the stanchion to effect movement of the first support plate toward and away from the second support plate. Movement of the first support plate toward the second support plate effects a closure of the mold sections carried on the support plates. Movement of the first support plate away from the second plate effects an opening of the mold sections carried on the support plates.
A pump means is also carried by the stanchion, and an injection tube extends outwardly from the pump means and is disposed in generally parallel relation to the longitudinal axis of the stanchion. The injection tube cooperates with a sprue opening through the second mold section such that continued movement of the first support plate in the direction which effects closure of the mold sections also moves the second support plate to bring the second mold section into engagement with the injection tube and axially translates the injection tube to actuate the pump means whereby to inject molten metal into the cavity of the closed mold.
When the subject apparatus is employed to make wheel weights a rail is provided sequentially to feed individual mounting clips to the mold. For convenience, each clip may be gravity fed to the lowermost, or second, mold section. The rim of the second mold section provides, in effect, an extension of the rail means whereby the clip can continue along the rim of the second mold section until it engages appropriate stop means. So positioned, a positioning lug associated with the injection tube rotates the clip to effect the desired orientation with respect to the mold cavity prior to, or simultaneously with, injection of molten metal into the cavity.
One preferred embodiment of apparatus for molding metallic apparatus according to the concept of the present invention is shown by way of example in the accompanying drawings without attempting to show all of the various forms and modifications in which the invention might be embodied; the invention being measured by the appended claims and not by the details of the specification.